Cellular toxicity mechanisms of lambda-cyhalothrin in Venus verrucosa as revealed by fatty acid composition, redox status and histopathological changes

Lambda-cyhalothrin (lambda-cyh), a synthetic pyrethroid type II, is one of the most toxic xenobiotics to aquatic organisms, which leads to a number of complex toxicological syndromes. The present study aimed to assess the adverse effects of lambda-cyh, on fatty acid (FA) composition, redox status, and the histopathology aspect of Venus verrucosa digestive gland under an exposure to a series of concentrations (100, 250 and 500 mu g/L). An increase of saturated fatty acid (SFAs) levels and a decrease of polyunsaturated fatty acids (PUFAs) content, mainly eicosapentaenoic (C20: 5n - 3, EPA) and docosahexaenoic (C22: 6n - 3, DHA) acids, were observed in lambda-cyh-treated digestive gland. Moreover, our data indicated an alteration in arachidonic acid (C20:4n - 6, ARA) level. The exposure to the highest dose of lambda-cyh promoted oxidative stress with an increase of malondialdehyde (MDA), advanced oxidation protein product (AOPP), metallothionein (MT) and hydrogen peroxide (H2O2) levels. A significant decrease in enzymatic (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)) and non-enzymatic (reduced glutathione (GSH), vitamin C and non-protein-SH (NPSH)) antioxidants was showed in treated groups. Moreover, acetylcholinesterase (AChE) activity was inhibited with the increase in lambda-cyh concentration. Our biochemicals results have been confirmed by the histopathological observations. Overall, our results indicated the toxic effect of lambda-cyh on the redox status of V. verrucosa digestive gland and highlighted the usefulness of determining FA composition in the better understanding of lambda-cyh toxicity.